Resumen de Estudio del papel de la proteína galphaq en mitocondria
The classical view of GPCRs and G proteins has given major emphasis in the signaling that occurs at the plasma membrane. But lately our view of the cellular location of these proteins is changing. Several studies have provided evidence of the presence of different components of the signaling machinery in other cellular compartments. As so, some GPCRs, have been detected at the nuclear membrane, as is the case of the receptors for endothelin ETaR and ETbR in cardiomyocytes or the receptor purinergic P2Y that localizes at the mitochondrial membranes. As for heterotrimeric G proteins, both G¿i and G¿12 proteins have been found at the mitochondria. During our study we discovered the presence of G¿q at the mitochondria. We performed fractionation (confirmed by MS), immunofluorescence studies to demonstrate that the endogenous G¿q is present at the inner membrane of the mitochondria of NIH3T3 cells and cardiac tissue. Particularly interested is the fact that the over-expression of G¿q induces a change in the morphology of mitochondria. Mitochondria appear elongated. On the other hand G¿q/G¿11 (-,-) MEF cells present mitochondria fragmented. In Mtn 2 (-,-) MEF cells overexpression of G¿q induces fusion. When MEF cells are treated with CCCP or express DRP1, mitochondria are fragmented. The presence of G¿q protects against fission. So G¿q could be playing a role in the fusion or fission of mitochondria.
